Thermocouple and pilot burner



we@ 22, WL. H. F, ALFERY 2,305,585

THERMOGOULE AND PILOT BURNER Filed April 13, 1939 INV ENTOR.

ATTORNEY 3 '5 Patented Dec.. 22, 1942 ,N1-ENT. oil-FICE Moconrrn AND rnor nonnen Henry F. Alfery, Milwaukee, Wis., assigner to Milwaukee Gas Specialty Company, Milwaukee, Wis., a corporation of Wisconsin Application April 13, 1939, Serial No.,267,731

(Cl. 13S-4) This invention relates to a thermocouple and pilot burner.

One of the main objects of the invention is to provide a combined thermocouple and pilot burner which is edective and reliable in operation and, at the same time, is simple and compact in construction and relatively inexpensive to build, assemble, and install.

Another object of the invention is to provide an improved form of thermocouple; also a. thermocouple provided with an extended fin in juxtapositioned to the thermal junction which is adapted to be heated for the purpose of increasing the amount of heat transmitted to this junction and thereby increasing the voltage of the thermo-electric current generated by the heating of the thermocouple.

It is also an object of the invention to provide a thermocouple and pilot burner as a unitary assembly that may be mounted as a unit, and

in which the desired position of the thermocouple relative to the pilot name is at all times assured; also a device of the character set forth having an improved relation and improved forms of connection between the various parts.

Further objects and advantages of the invention will appear from the following detailed description, taken in connection with the accompanylng drawing, in which:

Figure l is a detail longitudinal section through a combined thermocouple and pilot burner embodying the present invention;

Figure 2 is a similar section through another embodiment or the invention; and

Figure 3 is a fragmentary view of the thermocouple shown in Figure 1, showing the same provided with an extended fin in juxtaposition to the thermal junction which is adapted to be heated for a purpose which will hereinafter appear.

Referring now in detail to the drawing, the embodiment of the invention shown in Figure l comprises a metallic body member 5 having a passage t extending longitudinally therethrough.

Secured at 'l in one end of the body member t is an external metallic tubular lead member 8. The lead member 9 may be connected, for example, ln circuit with one side of the electromagnet of a safety control device of the general character disclosed in John H. Thornbery and Harold A. Mantz Patent No. 2,126,587, granted August 9, 1938, or it may be connected in circuit with any other suitable or preferred device. The lead member 8 with the metallic body member 5 the electromagnet and the external thermocouple element. j

The interior of the lead member 8 forms a gas or'fuel way I6 through which the gas or other suitable fuel is conducted to the pilot burner. The interior of th lead chamber 8 issuitably connected with the fuel supply line as shown. for example, in Vthe Patent 2,189,829 to Guido Wunsch and Josef Schuppert granted February 13, 1940; also in the Patent `2,271,506 to Harold A. Manta granted January 27, 1942; and in the Patent 2,198,896 to Theodore A. Wetzel granted April 30, 1940,or in any other suitable or preerred manner.

The interior Yfuel supply way l0 of the lead 8 opens into one end of the passage 6 and. at the adjacent end the body member E has a laterally extending portion i2, the interior I3 of which is supplied with fuel through a passage or port Hl leading from the passage t adjacent the end of the lead member 8.

A nozzle or iet member it is screwed at il into the laterally extending portion I2 of the body member d, and the fuel passes therethrough and outwardly through the orifice or port i8 at the outer end of the jet member. A sleeve 20 is screwed onto the nozzle or jet member i6 at 2l, and screwed at 22 into the outer end of the sleeve 2d is a second nozzle or jet member 29. The jet members it and 23 are thus disposed in coaxial spaced relation. A venturi member dit may be fixed, if desired, in the sleeve E@ between the jet members it and 23, although its use is not essential.

Where the fuel s of a character, such as gas. requiring admixture of air therewith, the air necessary to provide the desired gaseous mixture is admitted through an air inlet opening laterally through the sleeve 2t as shown in dotted lines at 2d. The air admitted through the inlet 9d and the fuel that issues from the orice or port it pass outwardly through the venturi 2,@ into the mixing chamber 28. The resulting gaseous mixture issues outwardly through the port 39 at the outer end of the jet member 23 and,

when ignited, forms the pilot llame indicated The thermocouple, indicated in its entirety at 35, comprises an external metallic tubular thermocouple element 36 of curved or angular form and an internal metallic thermocouple element 33 of dissimilar material disposed within the ex- -ternal element 36 and of corresponding curved constitude a lead conductor between one side ofr55 or angular form. The outer end of the internal thermocouple element 38 is joined to the outer end oi the external thermocouple element it to form a thermal junction at tt which is adapted to be heated by the pilot flame 32.

The opposite end oi the external thermocouple element 36 is brazed, welded, or otherwise suitably secured at 40 in the outer end of the body member E in amal alignment with the lead member The inner end of the internal thermocouple element 38 extends from the inner end of the external element 3B and into the passageway 6, where it is joined at 42 to the bared end of an internal lead conductor 43 to form an internal cold thermal junction. The attachment of the inner end of the external element 2t to the body member at 40 forms a second cold thermal junction.

'Ihe internal lead conductor 43, which is preferably covered with insulation as indicated at M, extends through the lead member 8 preferably to the position where it is connected in circuit with the other side of the electromagnet of the safety control or other device. 'Ihe metallic body member 5 constitutes not only a thermo-electric current conducting connection between the external thermocouple element 38 and the external metallic tubular lead member 8, but also forms an enclosure about the internal thermal junction t2. The internal thermal junction t2 in thus effectively insulated so as to maintain the heat transmitted to said -junction when the thermal Junction at 39 is heated by the pilot ilame, whereby the difference in temperature between the thermal liunction at 39 and the internal thermal junction at t2 is more quickly reduced when the heating of the junction 39 is discontinued. This makes for quicker operation of the safety control device to safety position when the pilot llame is extingushed.

The curved or angular form of the thermocouple 35 permits disposition of its inner end in axial alignment with the lead member t so that the desired connection may be provided between the thermocouple elements and the inner and outer lead conductors substantially in a straight line, and, at the same time, the outer end of the thermocouple is disposed in the path of the pilot flame 32 which issues in a direction substantially parallel with and odset laterally from the inner end of the thermocouple. The thermocouple and pilot burner constitute a unitary assembly that may be mounted as a unit and in which the desired position of the thermocouple relative to the pilot ame is at all times assured.

In one illustrative use of the device, the pilot burner is mounted in juxtaposition to a main burner (not shown) .for the purpose of igniting the same. As long as the pilot flame 22 is burning, the thermo-electric current set up thereby energizes the electromagnet to hold the safety control device in operating position. Upon extinguishment of the pilot name the electromagnet ceases to be energized suihciently to hold the sa'fety control device in operating position, and

.said control device moves to a safety position shutting off the fuel supply to the burner. This is all fully shown and described in the patent and copending applications herein mentioned, and therefore detailed illustration and description of the same will not be repeated here.

In practice, the tubular lead member 8 maybe suiiiciently ilexible to permit it to be-bent or turned to diierent positions or around corners to position the thermocouple and pilot burner as desired. At the same time, the lead member W may be of a character to support the thermocouple and pilot burner alter it is bent or turnel to the desired position. although of course sup porting brackets for supporting the thermocoupll and pilot burner may be employed and, therefore are contemplated within the scope oi the presen` invention.

'I'he embodiment of the invention illustrated ix Figure 2, except as will hereinafter appear, i: similar to the embodiment illustrated'in Figure 1 and like parts are indicated by primed reference characters corresponding with the reference characters used in Figure 1.

In the embodiment shown in Figure 2, the body member t' is shorter and the thermocouple 35', comprising external and internal thermocouple elements 36' and 38' Joined to form the hot thermal Junction at 39', is of straight or rectilinear form instead of being curved or angular as in the preceding embodiment of the invention.

The sleeve member 20' is screwed directly into the laterally extending portion i2' of the body member 5', and the nozzle or jet member I6' is secured, at Il in the sleeve member 20' instead of being screwed directly into the laterally extending portion l2' of thebody member 5' as before. 'I'he venturi and air inlet are indicated at 20' and 26' respectively, as in the preceding embodiment of the invention, but the nozzle or jet member 23', instead of having its port 2U' directed axially of the device, has this port 3U' directed obliquely toward the outer end of the thermocouple so that the pilot flame 32 will act upon or heat the thermocouple without making the thermocouple of curved or angular form to bring it into the path of the pilot flame.

If desired, the port 30' may be in axial alignment with the port I8', and a baille or system of baffles (not shown) may be employed to divert the ame to the thermocouple.

The advantages set forth in connection with the device shown in Figure 1 are secured with the device shown in Figure 2, and the device shown in Figure 2 is adapted for use in the manner described in connection with the device shown in Figure l, or in any other suitable or preferred manner.

In Figure 3 the thermocouple 35" comprises l the curved external and internal metallic thermocouple elements 36" and 38" joined at their outer ends to form the thermal junction 39" which is adapted to be heated by the pilot burner or other burner as in Figure 1. In this case, however, the outer end of the thermocouple is provided with an extended iin 50 in juxtaposition to the thermal junction 39". The fin 50 is preferably of metallic or other suitable heat conducting material, the particular iin 5l) shown being of annular form surrounding the thermal junction 39" and being joined or secured to the outer end of the thermocouple in any suitable or preferred manner, as indicated at 52.

In operation of the device shown fragmentarily in Figure 3, the iiame 32", which corresponds with the flame 32 in Figure 1, impinges upon and crawls outwardly along the curved thermocouple, spreading and playing around under the iin 50. 'I'he heat thus imparted to the iin 50 is transmitted to the hot Junction 39", increasing the amount of heat transmitted to the hot junction of the thermocouple from the llame 32", and thereby increasing the voltage of the thermoelectric current generated by the heat of the llame 32".

A iin, such as that above described, may be provided at the hot junction of the thermocouple shown in Figure `2, as well as on other forms of thermocouples within the scope of the broader )aspects of the present' invention.

I do not intend to be limited to the precise details shown or described.

-I claim:

l. A thermocouple, pilot burner, and lead connection comprising an external metallic tubular thermocouple element, an internal metallic thermocouple element disposed within said external thermocouple element and joined at one end to one end of said external thermocouple element to form a thermaldunction adapted to be heated, a metallic body member having an internal passage, the opposite end of said external thermocouple element being secured in said passage, an external tubular lead conductor joined to said body member, said external lead conductor supplying fuel into the passage in said body member, and an internal le'ad conductor extending through said external lead conductor and joined to the inner end of the internal thermocouple element within the passage in said body member, said body member having a port communicating with said passage and through which port fuel is discharged to maintain a pilot flame in position to heat the junction at the outer end of the thermocouple.

2. A thermocouple, pilot burner, and lead connection comprising an external metallic tubular thermocouple element, an internal metallic thermocouple element disposed Within said external thermocouple element and joined at one end to one end of said external thermocouple element to form a thermal junction adapted to be heated, a metallic body member having an internal passage. the oppositeend of said external thermocouple element being secured in said passage, an external tubular .lead conductor joined to said i body member, said'external lead conductor supplying fuel into the passage in said body member and connected in circuit with the external thermocouple element through said body member, an internal lead conductor extending through said external lead conductor and joined to the inner end of the internal thermocouple element within the passage in said body member, said body member having a port communicating with said passage and through which port fuel is discharged substantially axially from the outer end of the body member to maintain a pilot iiame and the outer end of. the thermocouple being turned laterally to position to be heated by said pilot flame.

3. A thermocouple, pilot burner, and lead connection comprising an external metallic tubular thermocouple element, an internal metallic thermocouple element disposed within said external thermocouple element and joined at one end to one end of said externalthermocoup'leelement to form a thermal junction adapted to be heated,y

a metallic body member having an internal passage, the oppositeend of said external thermocouple element being secured in said passage, an external tubular lead conductor joined to said body member, said external lead conductor supplying fuel into the passage in said body member and connected in circuit with the external thermocouple element through said body member, an internal lead conductor extending through said external lead conductor and joined to the inner end of the internal thermocouple element within the passage in said body member, the thermo- `an obliquely directed port communicating with said passage and through which port fuel is discharged obliquely to maintain a pilot flame in position to heat the outer end of said thermoco e.

A thermocouple, pilot burner, and lead connection comprising a conducting body member having a passage extending longitudinally therethrough, an external tubular lead conductor secured in one end of said passage, anexternal metallic tubular thermocouple element secured in the other end of said `passage, an internal thermocouple element disposed within said external thermocouple element and joined at its outer end to the outer end of said external element to form a thermal junction, the inner end of said internal thermocouple element extending from the inner end of said external thermocouple element and into the passage in said body member, said external lead conductor supplying fuel to said passage and connected in circuit with said external thermocouple element through said body member, and an internal lead conductor extending through said external lead conductor and joined to the inner end of the internal thermocouple element within said passage, said body member having a port communicating with said passage and through which port fuel is discharged to maintain a pilot ame in position to heat the junction at the outer end of the thermocouple.

5. A thermocouple, pilot burner, and lead connection comprising a conducting body member having a passage extending longitudinally therethrough, an external tubular lead conductor secured in one end of said passage, an external metallic tubular thermocouple element secured in the other end of said passage, an internal thermocouple element disposed within said external thermocouple element and joined at its outer end to the outer end of said external element to form a thermal junction, the inner end of said internal thermocouple element extending from the inner end of said external thermocouple element and into the passage in said body member, said external lead conductor supplying fuel to said passage and connected in circuit with said external thermocouple element through said body member, an internal lead conductor extending through said external'lead conductor and joined to the inner end of the internal thermocouple element within said passage, a pair oi coaxial jet members mounted on said body member laterally of said passage and communicating therewith, said jet members dening a space therebetween and one oi said jet members having 4a port through said body member and said body member having which fuel is discharged to maintain a pilot ame in position to heat the junction at the outer end of the thermocouple, and an air inlet port opening into the space between said jet members.

6. In a thermocouple, pilot burner, and lead connection, a conducting body member having a passage extending longitudinally therethrough, a thermocouple secured in one end of said passage and comprising a pair of thermocouple elements, an external tubular lead conductor secured in the other end of said passage, said external lead conductor supplying fuel to the pilot burner and connected in circuit with one of the .thermocouple elements, an internal lead conductor extending through said external lead conductor and connected in circuit with the other thermocouple element, and jet means on said body member laterally of said passage communicating with said passage for discharging fuel to maintain a pilot name in position to heat said thermocouple.

7. A thermocouple, pilot burner, and lead connection, comprising a conducting body member having a passage extending longitudinally therethrough, anexternal tubular lead conductor secured in one end of said passage, an external metallic tubular thermocouple element secured in the other end of said passage, an internal thermocouple element disposed within said external thermocouple element and joined at its outer end to the outer end of said external element to form a thermal junction, the inner end of said internal element extending from the inner end of said external element and into the passage in said body member, said external lead conductor supplying fuel to said passage and connected in circuit with said external thermocouple element through said body member, an internal lead conductor extending through said external lead conductor and joined/to the other end of the internal thermocouple element within said passage, a pair of coaxial jet members mounted on said body member laterally of said passage and communicating therewith, said iet members dening a space therebetween and one of said jet members having a port through which fuel is discharged substantially axially to maintain a pilot ilame, and an air inlet port opening into the space between said jet members, the outer end of the thermocouple being turned laterally to position to be heated by said pilot flame.

8. A thermocouple, pilot burner, and lead connection, comprising a conducting body member having a passage extending longitudinally therethrough, an external tubular lead conductor secured in one end of .said passage, an external metallic tubular thermocouple element secured in the other end of said passage, an internal thermocouple element disposed within said external thermocouple element and joined at its outer end to the outer end of said external element to form a thermal junction, the inner end of said internal element extending from the inner end of said external element and into 'the passage in said body member, said external lead conductor supplying fuel to said passage and connected in circuit with said external thermoasomar couple element through said body member, an internal lead conductorextending through said external lead conductor and joined to the inner end of the internal thermocouple element within said passage, the thermocouple extending substantially rectilinearly from said body member, a pair oi' coaxial jet members mounted on said body member laterally of said passage and communicating therewith, said `iet members defining a space therebetween and oneof said jet members having a port through which fuel is discharged obliquely to maintain a pilot iiame in position to heat the outer end of the thermocouple, and an air inlet port fopening into the space between said jet members.

9. A thermocouple comprising an external tubular thermocouple element and an internal thermocouple element extending through said external thermocouple element and joined at its outer end to the outer end of said external thermocouple element to form a thermojunction adapted to be heated by a ilame, and an extended heat conducting n mounted on the outer end of said external thermocouple element, said n extending outwardly from the external thermocouple element and operative to conilne a flame applied externally to the external thermocouple element inwardly of the outer end of the thermocouple and to conduct heat from the ilame to the thermojunction which is adapted to be heated by said llame.

10. In a device of the class described, an inner metallic thermocouple member, an outer tubular thermocouple member enclosing said inner thermocouple member and having an imperforate outer end Joined to the outer end of said inner thermocouple member to form a thermojunction adapted to be heated by a flame, and a heat conducting iin mounted on the outer end of the outer thermocouple member and extending outwardly from the imperforate outer end of said outer thermocouple member to confine a flame applied externally to said outer thermocouple member inwardly of the outer end thereof and to conduct the heat from the iiame to the thermojunctlon between the outer ends of said inner and outer thermocouple members.

' HENRY F. ALFERY. 

